Pointer authentication on aarch64 is pretty expensive (up to 50% of
execution time) when running a virtual machine with tcg and -cpu max
(which enables pauth=on).
The advice is always: use pauth-impdef=on.
Our documentation even mentions it "by default" in
docs/system/introduction.rst.
Thus, we change the default to use impdef by default. This does not
affect kvm or hvf acceleration, since pauth algorithm used is the one
from host cpu.
This change is retro compatible, in terms of cli, with previous
versions, as the semantic of using -cpu max,pauth-impdef=on, and -cpu
max,pauth-qarma3=on is preserved.
The new option introduced in previous patch and matching old default is
-cpu max,pauth-qarma5=on.
It is retro compatible with migration as well, by defining a backcompat
property, that will use qarma5 by default for virt machine <= 9.2.
Tested by saving and restoring a vm from qemu 9.2.0 into qemu-master
(10.0) for cpus neoverse-n2 and max.
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241219183211.3493974-3-pierrick.bouvier@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
At least for now cpu-topology is implemented only for KVM.
We already say this, but this tries to be more explicit,
and also show it in the examples.
This adds a new reference in the introduction that we can point to,
whenever we need to reference accelerators and how to select them.
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Message-ID: <20240314172218.16478-1-cfontana@suse.de>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Tested-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
HAX is deprecated since commits 73741fda6c ("MAINTAINERS: Abort
HAXM maintenance") and 90c167a1da ("docs/about/deprecated: Mark
HAXM in QEMU as deprecated"), released in v8.0.0.
Per the latest HAXM release (v7.8 [*]), the latest QEMU supported
is v7.2:
Note: Up to this release, HAXM supports QEMU from 2.9.0 to 7.2.0.
The next commit (da1b8ec072)
added:
HAXM v7.8.0 is our last release and we will not accept
pull requests or respond to issues after this.
It became very hard to build and test HAXM. Its previous
maintainers made it clear they won't help. It doesn't seem to be
a very good use of QEMU maintainers to spend their time in a dead
project. Save our time by removing this orphan zombie code.
[*] https://github.com/intel/haxm/releases/tag/v7.8.0
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230831082016.60885-1-philmd@linaro.org>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1529
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Message-Id: <20230409201007.1157671-1-sw@weilnetz.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Drop the frankly misleading quickstart section for a more rounded
introduction section. This new section gives an overview of the
accelerators as well as a high level introduction to some of the key
features of the emulator. We also expand on a general form for a QEMU
command line with a hopefully not too scary worked example of what
this looks like.
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com>
Message-Id: <20230124180127.1881110-23-alex.bennee@linaro.org>
